Combustion calculator



Sept. 4, 1956 M. VERON ETAL coMBusTIoN CALCULATOR Filed June 50, 1952 l .wieg :Aw-Eg INU/cm oF 1L 2,761,619 Ice Patented Sept. 4, 1956 COMBUSTION CALCULATOR Marcel Veron, Neuilly-sur-Seine, and Andr Dumez, Saint-Cloud, France Application `lune 30, 1952, Serial No. 296,274

Claims priority, application France June 30, 1951 2 Claims. (Cl. 235-61) The present invention has for its object to provide a combustion calculator, that is to say a device enabling the conditions of a `combustion to be determined from the indications of the volumetric anaylsis of the products of combustion, and also the modifications to be made to the air control so as to improve the combustion.

One of the special features of the invention consists in that the combustion calculator can be used directly for all types of fuel and for all types of combustion, whether the latter are neutral, oxidizing or reducing in .their nature.

A further feature `of the invention resides in that the combustion calculator is simple to operate and gives easy and exact readings.

The attached drawings illustrate the combustion calculator in accordance with the invention.

Fig. l is a plan view;

Fig. 2 is a partial detail view to a larger scale.

The combustion calculator consists of a disc in the center of which is mounted a shaft 11. On this shaft is mounted a pivoted slide-rule 12 carrying a graduated sliding plate 13. A curser 14 is adapted to slide on .the plate 13. The edge 15 of the plate 13 is aligned with the shaft 11 in such a way that the edge 15 is always placed along a radius of the disc 10.

The disc 10 comprises a central portion 16 bounded by a circle 17 and an annular portion 18 included between the circle 17 and the external circle 19. Inside the zones 16 and 18 are traced several families of graduated curves. In the central portion there is drawn a family of Archimedean spirals 20 graduated and representing the values of the proportions a of carbon dioxide CO2 contained in thesmoke generated by the combustion.

In the annular portion 18 are drawn two series of curves; the curves 21 which are portions of Archimedean spirals representing the proportions of carbon monoxide CO contained in the smoke, the curves 22, which are also portions of Archimedean spirals, presenting the values of the proportions w of oxygen O2 contained in the smoke.

The justication of the shape and the description of these curves 20, 21 and 22, results from the analytical transformation of the chemical equations of combustion. (The corresponding calculations have been given in detail in the Bulletin Technique de la Socit Franaise des Constructions, Babcock & Wilcox, No. 25, October 1952.)

In addition to the curves 21 and 22, there may also be drawn inside the annular space 17, the portions of curves 23 representing the values of the excess air X in the products of combustion; these curves are also Archimedean spirals.

The various curves 21, 22 and 23 intersect each other at suciently `wide angles to permit of easy and accurate reading, while in the usual types of combustion diagram, the network of the lines of equal values of a, w, and X are groups of convergent straight lines, the density of the groups often making readings both difficult and inexact.

The external circley 19 carries a graduation 24 of values of the sensible heat q of the smoke or indices of the volume v of the smoke. The index v expresses the ratio of volume of smoke actually produced by the combustion of a unit mass of fuel tothe volume of smoke which would be produced by a neutral combustion of a unit mass of the same fuel.

The edge 15 of the plate 13 is marked with graduations 25 representing the values of the content ao of carbon dioxide CO2 in the smoke which would be theoretically produced in the neutral combustion of the fuel considered. In addition, a further series of graduations 26 is arranged on the edge 15, representing the values of the indices l of latent heat contained in the products of combustion. This latent heat corresponds to the quantities of heat which could be supplied by the combustible gases, carbon monoxide CO, hydrogen H, hydro-carbons, contained in the smoke. The datum point 27 at the extremity of the scale 26 corresponds to the value l=0.

The combustion calculator which has just been described enables solutions to be found directly and without calculations of the problems presented by the combustion of all fuels. It should be noted that the graduations express the values of the quantities a, w, X, v, l, q, which are ratios independent of the nature of the fuel chosen. The calculator can thus be used for all the usual fuels, solid, liquid or gaseous.

A few examples of solutions of the problem of combustion are given below.

1) The proportions of carbon monoxide CO and w of oxygen O2 contained in the smoke are known.

The spirals 21 and 22 corresponding to the values and w are marked off or alternatively the curves which correspond to the values and w are estimated by interpolation between the nearest corresponding curves of the family of curves 21 and 22.

The intersection of these curves gives the figurative point 28. Through this point passes a curve 23, real or interpolated, the value of which gives the index of excess of air x.

The edge 15 of the rule 13 is now brought on to the point 28 and at 29 on the external graduation 24, the value of the index of volume v is read olf. By causing the 'latter to slide so that the datum point 26 comes opposite the point 28, the value of the index l of latent heat can then be read at 30 on the graduation 26 opposite the circle 17.

The curser 14 is then moved along its slide until its index such as 32 reaches a position on the value of the scale 25 which corresponds to the value a0 of the fuel used, this value being known beforehand and varying in practice from 15 for a light fuel to 20.5 for coke. The point 33 of the corresponding edge 15 comes on a curve 20 or between two graduated curves 20, giving the value of (the proportion of CO2) of the real combustion.

(2) The proportions a of carbon dioxide CO2 and w of oxygen O2 contained in the smoke are already known.

The curser 14 is moved along the rule 13 in such a way that its index 32 comes opposite the value of the graduation 25 corresponding to the known index a0 of the fuel used at 33, and that the datum mark 27 falls on the curve 22 corresponding to the value w.

The rule 12 is now rotated and the plate 13 is moved along at the same time so as to bring the point 33 on to the curve 20 corresponding to the value a.

Opposite the datum mark 27 of the plate 13, the values (content of CO) and x (excess of air), can be read oit directly on the curves or between the curves 21, 22 and 23 respectively.

The value of v is read at 29 on the scale 26, and the value of l at 30 on the same scale.

(3) The values of the proportions a of the carbon dioxide CO2 and I8 of carbon monoxide present in the smoke, are already known.

By sliding the curser 14, the index 32 is brought oppsite the value of the graduation 2S giving the value oro of the fuel utilized.

By rotating the rule 12 and sliding the plate 13, the datum mark 27 is brought on to the curve 21 corresponding to the value and at the same time the datum 32 is brought on to the curve 20 corresponding to the value nc.

The values of the contents of oxygen w and excess of air x are read off on or between the curves 2?; and 23 respectively. The value v is read oif at 29, and the index l at 30.

(4) The values of the proportions @(COz), (CO) and w(O2) contained in the smoke are already known.

The datum mark 28 having been brought to the intersection of the curves 21 and 22 corresponding to ,8 and o, the index 32 brought to the value al, of the scale 25 should come on to the curve 20 corresponding to ct. If not, the analysis is wrong.

If the value of a0 is not known, this can be taken from the scale 26 by bringing the index 32 on to the curve 2t) corresponding to the value u.

It will be seen that, by means of the combustion calculator described, there may be obtained directly and very rapidly, starting from the proportions of two constituents of the smoke, all the elements necessary for the regulation of the combustion; excess or shortage of air, sensible or latent losses of the smoke.

What we claim is:

1. A combustion calculator comprising a stationary circular carrier surface including a central circular area and an annular area concentrically enclosing the central area, the latter being provided with a group of scalecarrying Archimedean spirals defining values of the contents of carbon dioxide in the combustion gases and the annular area carrying two groups of spiral curves crossing each other, the rst series forming a scale of contents of carbon monoxide in the combustion gases and the second series forming a scale of contents of oxygen in the combustion gases, an index bar pivotally secured to the center of the circular carrier surface, a ruler slidingly carried by the index bar to move longitudinally thereof and carrying a scale of contents of carbon dioxide in the neutral combustion gases and a reference runner slidingly carried by the index bar.

2. A combustion calculator comprising a stationary circular carrier surface including a central circular area and an annular area concentrically enclosing the central area, the latter being provided with a group of scalecarrying Archimedean spirals defining values of the cor.- tents of carbon dioxide in the combustion gases and the annular area carrying three groups of spiral curves crossing one another, the first series forming a scale of carbon monoxide contents in the combustion gases and the second series forming a scale of oxygen contents in the combustion gases, the third series forming a scale of percentages of excess of combustion air, a circular scale of indicia of volumes of combustion gases and of free heat in the combustion gases, said circular scale being carried on the outside of the annular area by the carrier surface, an index bar pivotally secured to the center of the circular carrier surface, a ruler slidingly carried by the index bar to move longitudinally thereof and carrying two scales indicating respectively the contents of carbon dioxide in the neutral gases and the indicia of latent heat in the combustion gases, and two reference runners slidingly carried by the index bar and rigid with each other.

References Cited in the le of this patent UNITED STATES PATENTS 

